class Solution(object):
    def plusOne(self, digits):
        """
        :type digits: List[int]
        :rtype: List[int]
        """
        nums_string = ''.join(str(i) for i in digits)
        nums = int(nums_string)
        nums += 1
        num2string = str(nums)
        string2list = list(num2string)
        result_list = []
        for i in string2list:
            i = int(i)
            result_list.append(i)
        return result_list


if __name__ == '__main__':
    s = Solution()
    print(s.plusOne([9, 9, 9]))
